unixhost> perl -ew 'eval "$foo = { bar => () };";'

If I use -we instead of -ew, I do get the warnings with eval, too...

$ perl -we 'eval "$foo = { bar => () };";'
Name "main::foo" used only once: possible typo at -e line 1.
Use of uninitialized value in concatenation (.) or string at -e line 1
+.
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(I figure that with -ew, the program is just the bareword "w", which is being passed the rest of the commandline as arguments :)